Molecular cloning, expression, and enzymatic analysis of cathepsin X from starfish (Asterina pectinifera)

Characterization of a novel dipeptidyl peptidase 1 of Trichinella spiralis and its participation in larval invasion

The research aimed to describe a new Trichinella spiralis dipeptidyl peptidase 1 (TsDPP1) and investigate its functions in the larval invasion of intestinal epithelial cells (IECs). The gene TsDPP1 was successfully replicated and produced in Escherichia coli BL21 (DE3), showing a strong immune response. TsDPP1 was detected in diverse stages of T. spiralis and showed significant expression in the intestine infective larvae (IIL) and adult worms at 6 days post infection, as confirmed by qPCR and Western blot analysis. The primary localization of TsDPP1 in this parasite was observed in cuticles, stichosomes, and embryos by using the indirect immunofluorescence assay (IIFA). rTsDPP1 exhibited the enzymatic function of natural dipeptidyl peptidase and showed specific binding to IECs, and the binding site was found to be localized on cell membrane. Following transfection with dsRNA-TsDPP1, the expression of TsDPP1 mRNA and protein in muscle larvae (ML) were decreased by approximately 63.52 % and 58.68 %, correspondingly. The activity of TsDPP1 in the ML and IIL treated with dsRNA-TsDPP1 was reduced by 42.98 % and 45.07 %, respectively. The acceleration of larval invasion of IECs was observed with rTsDPP1, while the invasion was suppressed by anti-rTsDPP1 serum. The ability of the larvae treated with dsRNA-TsDPP1 to invade IECs was hindered by 31.23 %. In mice infected with dsRNA-treated ML, the intestinal IIL, and adults experienced a significant decrease in worm burdens and a noticeable reduction in adult female length and fecundity compared to the PBS group. These findings indicated that TsDPP1 significantly impedes the invasion, growth, and reproductive capacity of T. spiralis in intestines, suggesting its potential as a target for anti-Trichinella vaccines.

Genomic and transcriptomic identification of the cathepsin superfamily in the Mediterranean mussel Mytilus galloprovincialis

Cathepsins are lysosomal enzymes that participate in important physiological processes, such as development, tissue remodelling, senescence and innate and adaptive immunity. The description of these proteins in molluscs is fragmented and incomplete. In the present work, we identified most of the cathepsin family members in the bivalve Mytilus galloprovincialis by screening published genomic and transcriptomic information. In this specie, the cathepsin family is composed of 41 proteins showing a high diversification of cathepsins D, L and F, not previously observed in other taxonomic groups. Specific set of cathepsins are constitutively expressed in the different mussel tissues. Transcriptomic analyses suggested coordinated activity of the different cathepsins and their sequential activation during larval development. Cathepsins also play an important role in the immune response of bivalves, and different immune pathways seem to be activated in response to Vibrio splendidus infection.

Characterization of a Trichinella spiralis cathepsin X and its promotion for the larval invasion of mouse intestinal epithelial cells

The aim of this study was to ascertain the characteristics of a Trichinella spiralis cathepsin X (TsCX) and its role on larval invasion of intestinal epithelial cells (IECs). The full-length of TsCX cDNA sequence was cloned and expressed in Escherichia coli BL21. The results of RT-PCR, IFA and Western blot revealed that TsCX was expressed at T. spiralis muscle larvae (ML), intestinal infective larvae, adult worm and newborn larvae, and it was located in whole worm section. The results of Far western and confocal microscopy demonstrated that there was a specific binding of rTsCX and IEC, and the binding site was located within the IEC cytoplasm. rTsCX promoted T. spiralis larval invasion of mouse IECs while anti-rTsCX antibody inhibited larval invasion into the IECs. Silencing TsCX by specific siRNA reduced the TsCX expression and larval invasive capacity. These results indicated that TsCX specifically binds to IECs and promotes larval invasion of intestinal epithelia, and it might be a potential target of vaccines against enteral stages of T. spiralis.

Sorcin induces gastric cancer cell migration and invasion contributing to STAT3 activation

Gastric cancer (GC) is a globally occurring malignancy that is characterized by a high mortality rate due to a high tendency to metastasize and poor prognoses. Sorcin, as known as SRI, a soluble resistance-related calcium-binding protein, plays a significant role in multidrug resistance. Sorcin is related to the migration and invasion of cancer cells. However, the mechanism remains unclear. Here, we used immunohistochemistry to confirm that the expression of sorcin in cancer tissues is higher than that in the adjacent normal tissues. The wound healing and transwell results indicate that sorcin can induce migration and invasion of GC cells. To explore the role of sorcin in GC metastasis, isobaric tags for relative and absolutely quantitation (iTRAQ) were used to examine cells with and without sorcin knockdown to identify the differentially expressed proteins (DEPs). The results were evaluated via RT-PCR and western blot to confirm the ITRAQ data. Inhibition of sorcin expression can down- regulate the expression of CTSZ, MMP2, MMP9 and p-STAT3 followed by suppression of tumor growth and metastasis. Together, we concluded that sorcin has a oncogenic activity via inducing tumor growth and metastasis, leading to development of therapeutic treatments for GC.